How does engine compression get into the oilpan of a diesel engine?

Answer 1

1. When the piston rings gets weak the piston take an different agnle for its motion it acuse wear and tear in the cylinder liner and become oval shape there fore the pistor ring can't hold the compression properly

2. Hot spots

3. Back fire

Another answer

I have been a mechanic for 40 years, and the above answer is not correct, Diesels do not backfire, hot spots have nothing to do with Blow by, rings never take a different angle. Not to say that rings cannot wear and loose their knife edge that helps to remove varnish created by oxidized oil on the cylinder walls causing an un even surface and letting compression BLOW BY, as well as carbon acid that is formed in the combustion cycle.

There is a product that can help restore the seal of the rings and stop the wear, I have used Cerma with STM-3 for the last 10 years and it seems to correct the problem with stuck rings due to lacquer build up on the walls of the cylinder. Cerma products have help my business when all other ideas failed, short of a complete rebuild.

3rd try: Ring, cylinder and piston wear if it happened slowly over time. I see quite a few sudden failures now, which is caused by burned or holed pistons. Plan on a complete overhaul.

Hate to disagree with you on the backfire issue. But diesels can backfire. I was in a pit with one that did. Couldn't hear for about an hour. Another one blew a muffler apart. Rare but it can happen. Agree with the rest of your post. Where can you buy Cerma.